Brown corundum， also known as emery， is a tan artificial corundum made by melting and reducing three raw materials of bauxite， carbon material and iron filings in an electric arc furnace. The main chemical composition of brown fused alumina is AL2O3， which is from 95.00% to 97.00%， and contains a small amount of Fe， Si， Ti， etc. Brown corundum is the most basic abrasive， because of its good grinding performance， wide application range and low price， it is widely used.